JSR107: The new Caching Standard...JSR107: Java Caching Standard •javax.cache.Cache •Being developed by JSR107 •Java 6 and above is required •Included in JSR 342: Java EE 7

JSR107: The new Caching Standard

Greg Luck CTO Terracotta/Founder Ehcache

JFokus 2012

Wednesday, 15 February 2012


What is Caching?Temporary Storage of data or results that are likely to be used more than once

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Caching Characteristics• Fastest To Implement• Offload• Performance• Scale up• Scale out (Distributed Caches Only)• Buffer against load variability

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Maximising Cache Efficiency

cache efficiency = cache hits / total hits

➡ High efficiency = high offload➡ High efficiency = high performance

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Caching Use Cases


Sca

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Scale OUT

Commodity Server

Application

Types of Scaling


Sca

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Scale OUT

Commodity Server

Application

Types of Scaling

StandaloneCaching(in-process)

DistributedCaching

Types of Caching


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Local Disk Store(Re-Startable)

Local Storage

HeapStore

BigMemoryOff-Heap Store

5,000,000+

1,000,000

2

500

1,000+

Speed (TPS) Size (GB)

Scaling Example: Ehcache

100,000


824

Local Disk Store(Re-Startable)

Local Storage

HeapStore

BigMemoryOff-Heap Store

5,000,000+

1,000,000

2

500

1,000+

Speed (TPS) Size (GB)

Scaling Example: Ehcache

100,000

10,000s

Network Storage

Terracotta Server Array 1,000s


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Network Topology Example: Ehcache

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L1 L2

ELC

Eventual consistencyStrong consistencyLocal Transac=onsExplicit LockingXA Transac=ons

PACAc=ons on par==on: -‐ excep=on, -‐ noop-‐ local reads

Par==on healing: -‐ reconnect-‐ rejoin


Compared to NoSQL• NoSQL focused on persistence - Caching on temporary Storage

• NoSQL focused on BigData - Caching on valuable data• Caching focused on RAM storage• Caches are key-value stores, like key-value NoSQL• Caching is a use case for NoSQL• Much Lower latencies

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•! 95/5 Read/update

Comment: Sherpa does very well here, with better read latency – only one lookup into a B-tree is needed for reads, unlike log-structured systems where records must be reconstructed. Cassandra also performs well, matching Sherpa until high throughputs. HBase does well also, although read time is higher.

Workload B – Read heavy

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Throughput (operations/sec)

Workload B - Read latency

Cassandra HBase Sherpa MySQL

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Workload B - Update latency

Cassandra Hbase Sherpa MySQL

The code is available publicly on GitHub: https://github.com/brianfrankcooper/YCSB

Comparative Speeds


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Comparative Speeds


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Compared with hybrid in-‐process and distributed cache:

Latency = L1 speed * propor=on + L2 speed * propor=on

Comparative Speeds


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L1 = 0ms (< 5us) for on-‐heap and 50-‐100 us off-‐heapL2 = 2-‐3ms

80% L1 Pareto Model:

= 0 * .8 + 3 * .2= .6 ms

Comparative Speeds


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L1 = 0ms (< 5us) for on-‐heap and 50-‐100 us off-‐heapL2 = 2-‐3ms


= 0 * .8 + 3 * .2= .6 ms


latency = 0 * .9 + 3 * .1= .3 ms

Comparative Speeds


Compared to (Concurrent)Map

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• a Map is an in-process key-value store

Even local in caches add:

- expiry- eviction once full of least valuable entries

• Map is always store by reference• Caches typically are distributed


JSR107: Java Caching Standard• javax.cache.Cache• Being developed by JSR107• Java 6 and above is required• Included in JSR 342: Java EE 7 due end of 2012• Immediately usable by Java EE 6 and Spring• Immediately usable by any Java based app

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Open, Transparent Standards Approach• Terracotta and Oracle have tasked an FTE (Greg and Yannis) with developing the spec

• Developed in the open• 15 expert group members• Lots of healthy debate. See the mailing list: [email protected]

• Specification is standard spec license - free to use and implement

• Reference Implementation is Apache 2• Tests which is the major part of the TCK is Apache 2

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mailto:[email protected]

mailto:[email protected]

Expected Implementations• Terracotta - Ehcache• Oracle - Coherence• JBoss - Infinispan• IBM - ExtemeScale• SpringSource - Gemfire• GridGain • TMax• Google App Engine Java memcache client• Spymemcache memcache client

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Getting StartedAPI in Maven Central<dependency> <groupId>javax.cache</groupId> <artifactId>cache-api</artifactId> <version>0.3-SNAPSHOT</version></dependency>

Everything to get startedhttps://github.com/jsr107/jsr107spec

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Key Concepts• CacheManager => Caches• Cache => Entries • Entry => Key, Value• The basic API can be thought of map--like with the following additional features:

• atomic operations, similar to java.util.ConcurrentMap• read-through caching• write-through caching• cache event listeners• statistics

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API FeaturesMap-like with the following additional features:• atomic operations, similar to java.util.ConcurrentMap• read-through caching• write-through caching• cache event listeners• statistics• transactions including all isolation levels • caching annotations• generics

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How to Please Everyone - No Dependencies• Java SE - no dependencies. • EE/Spring - provided dependencies - they are already there.

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How to Please Everyone - Optional FeaturesOptional Features are:

• storeByReference• XA and Local Transactions • Caching Interceptor Annotations e.g.

Options interrogation at runtime via Capabilities API:• ServiceProvider.isSupported(OptionalFeature feature)• CacheManager.isSupported(OptionalFeature feature)

Works for implementers and Users20


Aimed at Standalone and Distributed CachingStandalone Features

• storeByReference - allows speeds similar to CHM• CacheEventListener callbacks - useful for triggering eventsDistributed Features

• storeByValue• NotificationScope in CacheEventListener• modifications/differences to Map and ConcurrentHashMap to reduce network cost. e.g. - No values() and many others. - Calls may not return a value e.g. remove(Object key) returns boolean rather than the old value 21


Not a Data Grid Specification• Infinispan, Coherence and Extreme Scale are Data Grids• Ehcache and Memcache are distributed client-server caches• NoSQL key value stores are distributed client-server key stores which could be used for cachingSo:

• JSR107 does not mandate a topology• JSR347 does - it is for data grids and builds on JSR107

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Classloading• Caches contain data shared by multiple threads/JVMs which may be using Java SE, EE, OSGi or custom class loading.

• This makes class loading tricky• A classloader can be specified when the CacheManager is created or a default is used. Either way all classes will be loaded by the CacheManager’s classloader, not the environment’s classloader.

• public static CacheManager getCacheManager(ClassLoader classLoader)

• public static CacheManager getCacheManager(ClassLoader classLoader, String name) 23


Creating a CacheManagerServiceLoader CreationWe support the Java 6 java.util.ServiceLoader creational approach. It will automaticaly detect a cache implementation in your classpath. You then create a CacheManager with:CacheManager cacheManager = CacheManagerFactory.getCacheManager();or more fully:CacheManager cacheManager = CacheManagerFactory.getCacheManager(“app1”, Thread.currentThread().getContextClassLoader());

“new” CreationCacheManager cacheManager = new RICacheManager(“app1”, Thread.currentThread().getContextClassLoader());

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Creating a CacheTo programmatically configure a cache named “testCache” which is set for read-through

CacheManager cacheManager = getCacheManager();Cache testCache = cacheManager.createCacheBuilder(“testCache).setReadThrough(true).setSize(Size.UNLIMITED)..setExpiry(Duration.ETERNAL).build();

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Using a CacheYou get caches from the CacheManager. To get a cache called “testCache”:

Cache<Integer, Date> cache = cacheManager.getCache(“testCache”);

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Putting a value in a CacheCache<Integer, Date> cache = cacheManager.getCache(cacheName);Date value1 = new Date();Integer key = 1;cache.put(key, value1);

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Getting a ValueCache<Integer, Date> cache = cacheManager.getCache(cacheName);Date value2 = cache.get(key);

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Removing a mappingCache<Integer, Date> cache = cacheManager.getCache(cacheName);Integer key = 1;cache.remove(1);

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Exposing the underlying Cache’s APIUnwrap Method on Cache <T> T unwrap(java.lang.Class<T> cls);

Ehcache Examplenet.sf.ehcache.Cache cache = javax.cache.cache.unwrap(net.sf.ehcache.Cache.class);

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IDE API Review

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AnnotationsJSR107 introduces a standardised set of caching annotations, which do method level caching interception on annotated classes running in dependency injection containers. Caching annotations are becoming increasingly popular:

•Ehcache Annotations for Spring•Spring 3’s caching annotations.

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http://code.google.com/p/ehcache-spring-annotations/

http://code.google.com/p/ehcache-spring-annotations/

Annotation OperationsThe JSR107 annotations cover the most common cache operations including:

•@CacheResult•@CachePut•@CacheRemoveEntry•@CacheRemoveAll

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Specific Overrides

public class DomainDao { @CachePut(cacheName="domainCache") public void updateDomain(String domainId, @CacheKeyParam int index, @CacheValue Domain domain) { ... } }

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Fully Annotated Class Examplepublic class BlogManager {

@CacheResult(cacheName="blogManager") public Blog getBlogEntry(String title) {...}

@CacheRemoveEntry(cacheName="blogManager") public void removeBlogEntry(String title) {...}

@CacheRemoveAll(cacheName="blogManager") public void removeAllBlogs() {...}

@CachePut(cacheName=”blogManager”) public void createEntry(@CacheKeyParam String title, @CacheValue Blog blog) {...}

@CacheResult(cacheName="blogManager") public Blog getEntryCached(String randomArg, @CacheKeyParam String title){...}}

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Wiring Up Spring<beans ...> <context:annotation-config/> <jcache-spring:annotation-driven proxy-target-class="true"/> <bean id="cacheManager" class="javax.cache.Caching" factory-method="getCacheManager" /> <bean class="manager.CacheNameOnEachMethodBlogManagerImpl"/> <bean class="manager.ClassLevelCacheConfigBlogManagerImpl"/> <bean class="manager.UsingDefaultCacheNameBlogManagerImpl"/></beans>

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Wiring Up CDI1. Create an implementation of javax.cache.annotation.BeanProvider

2. Declare a resource named javax.cache.annotation.BeanProvider in the classpath at /META-INF/services/.

For an example using the Weld implementation of CDI, see the CdiBeanProvider in our CDI test harness.

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More InformationJumping Off Point to Everything Elsehttps://github.com/jsr107/jsr107spec

Maven Snippet<dependency> <groupId>javax.cache</groupId> <artifactId>cache-api</artifactId> <version>0.x</version></dependency>

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https://github.com/jsr107/jsr107spec

https://github.com/jsr107/jsr107spec

Documents

JSR107: The new Caching Standard...JSR107: Java Caching Standard •javax.cache.Cache •Being developed by JSR107 •Java 6 and above is required •Included in JSR 342: Java EE 7